Lock-joint roofing



Oct. 3, 1944.

J. M. FERGUSON 2,359,633

Loox-JOINTv RooFING Filed July 2l, 1942 F/cv. 4

B James /17 F/"guson 'y Patented ct.l 3, '1944 UNITED STATES PATENT OFFICE y LocKJomTnooFING James Melville Ferguson, Denver, Colo.' Application July 21,` '1942, Serial No. 451,686

4 claims. (ci. 10s-7) i This invention relates to roofing material such as is commonly employed in ro1l, strip, or sheet form as an outer covering for roofs of buildings, either in single sheet thickness or in superposed layers constituting so-called built-up roofs, and has as an object to provide an improved form and construction for such roofing material.

A further object of the invention is to provide an improved construction of roofing material designed to facilitate sealing cooperation be tween cooperating margins of adjacent sections of such material.

A further object ofthe invention is to'provide an improved construction of rooting material designed to obviate certain disadvantages of conventional material of similar type.

A further object of the invention is to provide an improved construction of roofing material particularly adapted for use in superposed layers for the development of smooth, durable, weathertight, multiple-ply roofs. v

My invention consists in the construction, arrangement, and combination of elements hereinafter set forth, pointedout in my claims and illustrated by the accompanying drawing, in

which- Figure-1^ is a fragmentary, isometric view of E,

a roof corner of a conventional building cone struction wherewith theimprovements constituting my invention have been operatively associated, a flap element of the improved roofing material being shown bent away from the plane of the roof as it would appear during application 4of the material to the roof. Figure 2 is a fragmentary, isometric view of conventional roof construction illustrating, in somewhat exaggerated detail,'the usual practice of overlapping adjacent 1 margins of thematerial stripor sheet units to form water tight joints.v Figure 3 is a cross secv tiongthrough a laminated or built-upmroo developedthrou'gh use 'of my improved roong material. Figure 4 is a cross -section transversely o! a strip of rooiing material embodying the principles of my invention, the mid-portion of the strip being broken away to conserve space.. A

As a weather-proof outer covering for roofs oi.'l

many speciiic types andconstructions, relatively flexible sheet or strip units of felted material suitably impregnatedl with bitumen, asphalt, and like oils, has come into general andwide-spread use. Such roof coverings are applied-vin certain instances as single layers of the material and in other instances as a plurality of superposed'lay. ers cooperating to form a laminated roof of built-up type, it being Ycommon practice in the construction of either type of roof vto overlap adjacent margins of the material units in a given layer of the .material in the manner shown in Figure 2 in an eiort to adequately seal the joint between adjacent such units against the penetration of weather therethrough, a suitable binder, such as tar, liquid asphalt, cementitious material, or the like, being inserted as a seal between the overlap portions of the adjacent unit margins. This conventional practice has a notable disadvantage deriving frorn the fact that the roofing material must be abruptly. bent where one strip or sheet unit engages over the margin of an adjacent unit, as is clearly indicated inv Figure 2, and though vsuch material is characterized by considerable inherent exibility and may be readily bent without damage to overlap in the manner shown in Figure 2, such material in place of a roof tends to lose some of its initial flexibility as it Weathers and dries under the action of. the elements and develops' a degree of brittleness which results in cracking and fis'- suring of the material where bent to overlap along the edges of an adjacent unit, the impact effect of rain, hail, and wind, together with expansion and contraction of the material as a result of temperature changes, all serving to initiate and enhance the development of such cracks and fissures as thel material becomes relatively more brittle, it being obvious that any cracks. or iissures opening through the material units destroy the weather tight function of thecovering. Various expedients have been employed in an effort .to minimize the above-described disadvantage of the conventional material as commonly applied,

. but such expedients as have heretofore come into use have proved to be inadequate to the ends sought or impractical because of the increased expense of their use. To obviate the disadvantages above noted and to provide a construction and arrangement of roofing material susceptible of development in either strip or sheet form for convenient application asv "a weater-tight roofl covering in either single o r multiple layers, the

prime function and purposei=of-the invention as hereinafter set forth.

My improvement consists, simply, in forming the adjacent, cooperating margins of the sheets or strips of rooting material, during manufacture of such material, so that they may interengage to lform av conveniently sealable joint having a thickness no greater than that of the body of the material and thus eliminate abrupt bends or offsets in the material as applied. The

invention maybe applied to any suitable specific -arrangement and combinations of materials Aconstituting a exible sheet or' strip having weather-proong qualities, irrespective of the particular constituents or manner of their com bination, conventional practice being tof-form such material by impregnating a felted web of suitable iiber with weather-proong oils or admixtures and compacting'the product through suitablerolls. The invention consists in forming a relatively deep lgroove or channelin and opening marginally along one edge of the strip or sheet unit of the material and a corresponding tapered tongue along the opposite margin of the material unit, s o that said tongue is adapted to engage in and substantially fill the groove or channel of an adjacent unit.

As shown in the drawing, the numeral I Vdesignates the web or body portion of a conventional strip or sheet of felted roofing material substantially one-third of the unit width. The

intersection of the unit body portion by the groove or recess II results in the formation of relatively thin flaps I2 of the material disposed in spaced relation as dening walls on opposite sides of said groove or recess, which flaps I2 are relatively thin in section, highly flexible and hence susceptible of convenient bending relative to the body portion I0,.and are each tapered to an approximate featherv-edge" along their free mar- 'I'he margin of the body portion I0 opposite that intersected by the groove or recess II is reduced in thickness by any means suitable to such purpose vto form a 4tongue I3 coextensive with the corresponding margin of the unit, which tongue I3 is vso dimensioned, positioned, and contoured as to fit freely within and substantially iill the groove or recess II of an adjacent unit of the material, the tongue I3 preferably being slightly smaller than its associated recess II so as to provide a space about said tongue when engaged within a recess II wherein suitable cementitious or sealing material may be disposed to effectively weather proof the joint thus formed.

In the practicaluse of roong material embodying the improvements shown and described,

a first strip or sheet unit is secured in covering` relationl with a roof portion in any suitable or usual manner which leavesthe upper of the unit flaps I2 free and unsecured, whereafter said upper flap4 I2 is bent upwardly away from the other or lower flap I2 and the thus exposed surface of said lower flap I2y is then coated with a suitable binder or cementing agent, whereupon the tongue'portion I3 of a second strip or sheet unit is overlapped on the coated lower flap I2 of the rst unit, the upper surface of said tongue portion coated with the binder or cementing agent, andthe upraised upper flap I2 is pressed against and in covering relation with said tongue portion to complete an eiiiciently sealed joint, the tapered character of the tongue portion and associated naps cooperating to produce a joint which lies flat and'is entirely free from abrupt bendsf shoulders, or oifsets formed in the material constituting the roong units. Figure 1 rality of single-layer roof coverings in the manner indicated by Figure 3, it being of course` preferable to stagger the joints between adjacent units in the respective layers of the multiple-ply roof and to bond the layers of lsuch a roof to each other with a suitable binder or cementing agent. Obviously, the end portionsl of the strip or sheet units may be formed with cooperating tongue and groove elements in a manner and for a purpose identical with that described in connection with the long margins of said units.

Since many changes, variations, and modifications in the specic form, construction, and relation of the elements shown and described may be had without departing from the spirit of my invention, I wish to be understood as being limited solely by the scope of the appended claims, rather than by any details of the illustrative showing and foregoing description.

I claim as my invention:

1. Roofing material comprising plane units of iiexible, felted material, each of said units being formed with a tongue portion of reduced thickness along one margin and a complementary, laterally-opening groove along its other margin, said groove being defined between separable naps each susceptible of being bent into substantially perpendicular relation with the plane of its unit to fully uncover the inner face of its associatedA 2. Roofing material comprising plane units of flexible, felted material each formed with a laterally and outwardly tapered tongue portion along and forming one of its margins, a laterally and inwardly tapered, complementary groove along and opening through the other unit margin, and v,separable ilaps, each susceptible of bej ing bent into substantially perpendicular relation with the plane of the unit to fully uncover the inner face of the associated nap, defining said flexible, felted material each formed with a latillustrates the manner in which a roof may be covered with a single layer or thickness of'material embodying the improvements of the instant invention, and it will be immediately aperally and outwardly tapered tongue portion along and forming one of its margins, a laterally and inwardly tapered, complementary groove along and opening through the other unit margin, and separable flaps, each having such thickness at its junction with the unit body as will permit of its being bent into substantially perpendicular relation therewith to fully uncover the inner face of the associated ilap, defining said groove.

4. In `flexible, felted roofing' material, means for interconnecting adjacent units of the material in a weather-proof joint having a thickness substantially equal to that of the body portion of the material, said means comprising a relatively-deep, inwardly tapered groove longitudinally along and opening marginally through one edge of the material to form spaced, cooperating, separable flaps of such thickness-adjacent their junction with the unit body portion as will permit of their being individually bent into substantially perpendicular relation with the unit Vbody portion to fully uncover the inner face of the associated flap, and a correspondingly and outwardly tapered tongue portion of reduced thickness longitudinally along and forming the opposite margin of each unit of the material and adapted for engagement and sealing between the groove flaps O an adjacent unit of the material.

JAMES FERGUsoN. 

